STYLE: add comment about the -D -P order and fix typo in doc

Alex

Source/cmRemoveDefinitionsCommand.h

@@ -66,7 +66,7 @@ public:
       "  REMOVE_DEFINITIONS(-DFOO -DBAR ...)\n"
       "Removes flags from command line of C and C++ compilers.  "
       "This command can be used to remove any flag from a compile line, "
-      "but the -D flag is accepted most C/C++ compilers.  "
+      "but the -D flag is accepted by most C/C++ compilers.  "
       "Other flags may not be as portable.";
     }
   

Source/cmakemain.cxx

@@ -79,7 +79,8 @@ static const cmDocumentationEntry cmDocumentationOptions[] =
   {"-P <file>", "Process script mode.",
    "Process the given cmake file as a script written in the CMake language.  "
    "No configure or generate step is performed and the cache is not"
-   " modified."},
+   " modified. If variables are defined using -D, this must be done "
+   "before the -P argument."},
   {"--graphviz=[file]", "Generate graphviz of dependencies.",
    "Generate a graphviz input file that will contain all the library and "
    "executable dependencies in the project."},